Electronic endoscopes typically comprise an imaging subassembly, comprising an image sensor and suitable optics, at the distal end of the endoscope insertion tube. The imaging subassembly is connected to wires that pass through the insertion tube to the proximal end of the endoscope, where they are connected to a video processor board. Typically, the video processor board provides power and control signals to the image sensor, and receives and processes raw video signals from the image sensor in order to generate standard video output.
Thus, in general, the electronics assembly of the endoscope (comprising the imaging subassembly, video processor board and connecting wires) can undergo final testing only after the entire endoscope has been assembled, whereupon the wires are connected to the imaging assembly at one end of the insertion tube and the video processor board at the other. If a fault in the electronics assembly is discovered at this late stage, it may be necessary to disassemble the entire endoscope in order to repair it.